1. Field of the Invention
The subject invention generally relates to a strut assembly for a vehicle.
2. Description of the Prior Art
U.S. Pat. No. 6,374,966 to Lillbacka discloses a strut assembly for a vehicle. The strut assembly comprises a hydraulic damper, i.e., a shock absorber. The hydraulic damper includes a housing including a first housing end and a second housing end. The housing defines a fluid cavity. The housing extends along a longitudinal axis. The hydraulic damper further includes a rod moveable relative to the housing along the longitudinal axis. The rod includes a first rod end disposed within the cavity and a second rod end spaced from the housing along the longitudinal axis. A mounting plate is coupled to the second rod end. The second housing end is disposed along the longitudinal axis nearer the mounting plate than the first housing end The mounting plate is configured for attachment to the vehicle. A mounting bracket is attached to the first housing end, and is also configured for attachment to the vehicle. A flexible membrane includes a first membrane end coupled to the housing and a second membrane end coupled to the mounting plate. The flexible membrane is configured to receive a pressurized gas to form an air spring. The Air spring biases the mounting plate away from the housing along the longitudinal axis. A coil spring is entirely disposed within the flexible membrane, and includes a first spring end and a second spring end. The first spring end is in engagement with the second housing end. The second spring end is in engagement with the mounting plate. The coil spring biases the mounting plate away from the housing along the longitudinal axis.
The coil spring of the strut assembly disclosed in U.S. Pat. No. 6,374,966 assists in preventing the rod from collapsing into the housing. However, the coil spring is insufficient to carry the load of a heavy-duty vehicle should the strut assembly lose air pressure to the air spring or should the hydraulic damper fail.